Add basic charger which does just read out simple registers without
doing any sophisticated things. 

This is a stripped down version of
https://lore.kernel.org/lkml/dbd97c1b0d715aa35a8b4d79741e433d97c562aa.1637061794.git.matti.vaittinen@fi.rohmeurope.com/

That version includes all the bells-and-whistles you might imagine
around coloumb counter handling and capacity measurement which includes
changes no the power supply core.
Rather do a step by step approach to keep that reviewable.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
Changes in v2:
- fix some be16 handling reported by bots
- fix some style issues
- do not sneak in additional chip ids
- remove useless debug output 
- remove wrong/useless alias
- remove fuel gauge remains
- fix error checks in temperature reading
- sync properties in switch/case with list
- Link to v1: https://lore.kernel.org/r/20250816-bd71828-charger-v1-0-71b11bde5c73@kemnade.info

---
Andreas Kemnade (1):
      power: supply: Add bd718(15/28/78) charger driver

Matti Vaittinen (1):
      mfd: bd71828, bd71815 prepare for power-supply support

 drivers/mfd/rohm-bd71828.c           |   44 +-
 drivers/power/supply/Kconfig         |    9 +
 drivers/power/supply/Makefile        |    1 +
 drivers/power/supply/bd71828-power.c | 1135 ++++++++++++++++++++++++++++++++++
 include/linux/mfd/rohm-bd71828.h     |   65 ++
 5 files changed, 1245 insertions(+), 9 deletions(-)
---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250816-bd71828-charger-9d187346f734

Best regards,
-- 
Andreas Kemnade <andreas@kemnade.info>